Continuing on from the experiments with pure waves, this week I decided to put the light sensor and arduino to the side and instead investigate the properties of subtle standing waves and their interaction with peripheral sound and feedback.

I made a very simple max patch which has two pure waves tuned an arbitrary minor third interval apart - i.e. cycle~ 1 @ approx. D2; cycle~2 @ approx. F2. Why are these frequencies approximate? Each of the pure waves has a perpetually triggered line object so that the respective frequency of each cycle~ is constantly moving 2Hz back and forth; so in this respect, the frequency is never stable and is constantly moving. The cycle~1 line object is set to a line~ duration of 10 seconds, whereas cycle~2 is set to 10.05 seconds. As the timings are slightly out of sync with each other, this creates a drifiting phase relation between them and renders *very* subtle wave interplay. When this is broadcast into an acoustic space (my studio), things get interesting.

To add a bit more complexity to this setup, I added a microphone connected to an amplifier. These were placed in close proximity with each other so as to create a very discrete feedback signal which is broadcast into the space. I liked the idea of introducing another signal into the space which could be influenced by the moving wave fronts. This took a fair bit of refinement since the feedback is influenced by the movement of the wave fronts. To add even more colour to the setup, I opened the balcony door of the studio so that the peripheral sounds of our neighborhood could drift into the space and subtly influence things - particularly the feedback.

Now this sounded pretty good on the recording (a handheld recorder placed in the middle of the space, facing the balcony), but I decided to go a little further and add an artificial reverberation in post-production.

Whilst this is a bit of a deviation from the previous two pieces, I really like what this reverberation does to the elements at play - especially the wave interplay and peripheral ambient sound.

Now how will I neatly wrap these experiments up next week?

Thanks again for listening!

Tags: acoustics, feedback, peripheral sound, pure waves, week 15 2018, View by:Tristan Louth-Robins